Plant and Pollinator Communities of High Elevation Rock Outcrops

Abstract

ABSTRACT: High-elevation rock outcrop ecosystems are home to a unique flora, with endemic and disjunct species hypothesized to be susceptible to shifts in species composition or phenology with climate warming. Easily accessed outcrops also are susceptible to human disturbance. We surveyed vegetation, flowering plant species, and insect pollinators on seven outcrops that range from relatively inaccessible to frequently visited to determine if: (1) vegetation composition or abundance correlates with accessibility; (2) establish baseline information on species composition and abundance; and (3) determine if specialized plant-pollinator interactions indicate susceptibility to shifts in flowering time. Richness of plant cover was not related to outcrop accessibility; however, the least accessible outcrop had the lowest frequency of bare rock, relatively high lichen cover, and vegetation patches with a distinct flora of spikemoss (Selaginella sp.), mosses, lichens, and vascular plants. Bare rock was most abunda...